1. Field of the Invention
The present invention relates to a group-III nitride semiconductor laser device, and a method for fabricating the group-III nitride semiconductor laser device.
2. Related Background Art
Patent Literature 1 (Japanese Patent Application Laid-open No. 2009-117494) discloses a method for fabricating a semiconductor device, comprising a step of forming first auxiliary grooves in a semiconductor device structure provided on a semiconductor substrate; a step of forming second auxiliary grooves in the semiconductor device structure; and a step of dividing the semiconductor substrate and the semiconductor device structure in division directions along the first auxiliary grooves and the second auxiliary grooves. In this fabrication method, a plurality of second auxiliary grooves are separately provided in the division directions, and at least two first auxiliary grooves are provided separately from each other between at least a set of adjacent second auxiliary grooves out of the plurality of second auxiliary grooves. Then the foregoing dividing step involves dividing a separate region between the two first auxiliary grooves. Non Patent Literature 1 (Jpn. J. Appl. Phys. Vol. 46, (2007) L444) discloses a semiconductor laser device with a hexagonal GaN substrate of a low stacking fault density having a semipolar surface (10-11) and a laser structure provided on the semipolar surface. A waveguide extends in an off direction of the c-axis of the hexagonal GaN substrate, and mirrors of the semiconductor laser are formed by reactive ion etching (RIE).